FIG. 1 shows a forklift including a conventional working vehicle heating and air conditioning system. Forklift 1 is provided with steering wheel 3 and a plurality of levers at the front of cabin 2. Heating and air conditioning unit 4 is disposed on the ceiling of cabin 2. Heating and air conditioning unit 4 is provided with air inlet port 5 and air outlet port 6 and includes evaporator 7, heater core 8, and fan 9. The air inside of cabin 2 flows into heating and air conditioning unit 4 through air inlet port 5 and is cooled or heated therein before flowing out through air outlet port 6 toward the front of cabin 2.
However, because this heating and air conditioning system for a working vehicle is disposed in cabin 2, the volume of usable space within cabin 2 decreases. Also, heated air emitted from heating and air conditioning unit 4 does not circulate sufficiently within cabin 2 because heating and air conditioning unit 4 is disposed on the ceiling of cabin 2. Air around the passenger's feet is not sufficiently heated and front glass 23 is not sufficiently defrosted.